Abstract: The influences of density and dimension of carbon nanotubes on their electron emis-sion from arrays are studied. The tip electric field of nanotubes, electric field enhance-ment factor, and optimum nanotube density are expressed by analytic equations. The theoretical analyses show that the field enhancement factor is sensitive to nanotube density, and can be sharply improved at a specific and optimum density. Some exper-iments have demonstrated these. Owning to electrostatic screening effect, the length of carbon nanotubes has little effect on their emission. A uniformly-distributed carbon nanotube array model is set up, and applied to analysis of carbon nanotube arrays.The results obtained here are in good agreement with the experimental data.

Key words: carbon nanotube array, field emission, optimum density,